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Chemistry Past Questions and Answers

Jamb 1979 Chemistry Questions

Question 21:
Indicate which of the following statements is not true as we move from left to right along the periodic Table:
  • A Atomic number of elements increases
  • B Atomic mass of elements increases
  • C Electropositive character of elements increases
  • D Electronegative character of elements increases
  • E Number of electrons in the outermost orbits of element increases
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Question 22:
0.1 Faraday of electricity was passed through a solution of copper (ll) sulphate. The maximum weight of copper deposited on the cathode would be [Cu = 64]
  • A 64.0g
  • B 32.0g
  • C 16.0g
  • D 6.4 g
  • E 3.2g
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Question 23:
Which one of these compounds will NOT give an oxygen gas on heating?
  • A Manganese dioxide
  • B Hydrogen peroxide
  • C Zinc nitrate
  • D Sodium nitrate
  • E Ammonium nitrate
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Question 24:
In the extraction of aluminum from purified bauxite by electrolysis, cryolite is used because
  • A It makes bauxite a better conductor of electricity
  • B It makes bauxite melt at a lower temperature
  • C It makes aluminium purer
  • D It prevents aluminium from getting oxidized
  • E It protects the carbon electrodes used in the process
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Question 25:
In the redox reaction 2Fe2+ + CI2 → 2Fe 3 + + 2Cl
  • A Cl<sub style='font-size: smaller;'>2</sub> is reduced because it has lost electrons
  • B Cl<sub style='font-size: smaller;'>2</sub> is reduced because its oxidation number has decreased
  • C Cl<sub style='font-size: smaller;'>2</sub> is reduced because its molecule is change to two ions
  • D Fe<sup style='font-size: smaller;'>2+</sup> is reduced because it has lost electrons
  • E Fe<sup style='font-size: smaller;'>2+</sup> is reduced because it has gained electrons
View Answer & Explanation